Cooling System

This application is a continuation of U.S. patent application Ser. No. 18/631,323 filed Apr. 10, 2024, published as U.S. Patent Publication No. 20240255195, by Shitong Zha et al., and entitled “COOLING SYSTEM”, which is a continuation of U.S. patent application Ser. No. 17/506,515 filed Oct. 20, 2021, now U.S. Pat. No. 11,988,423 issued May 21, 2024, by Shitong Zha et al., and entitled “COOLING SYSTEM”, which is a continuation of U.S. patent application Ser. No. 16/269,670 filed Feb. 7, 2019, now U.S. Pat. No. 11,209,199 issued Dec. 28, 2021, by Shitong Zha et al., and entitled “COOLING SYSTEM”, which are incorporated herein by reference.

This disclosure relates generally to a cooling system.

Cooling systems are used to cool spaces, such as residential dwellings, commercial buildings, and/or refrigeration units. These systems cycle a refrigerant (also referred to as charge) that is used to cool the spaces.

A typical commercial refrigeration system includes a medium temperature section (e.g., produce shelves) and a low temperature section (e.g., freezers). A low temperature compressor compresses the refrigerant from the low temperature section. A medium temperature compressor compresses a mixture of the refrigerant from the medium temperature section, a flash gas bypass from a flash tank, and/or the compressed refrigerant from the low temperature compressor. Thus, the temperature of the refrigerant from the low temperature section and the temperature of the refrigerant from the medium temperature section and/or gas from the flash tank affect the temperature of the mixture received at the medium temperature compressor. Typically, the refrigerant from the low temperature section heats the refrigerant from the medium temperature section and/or the gas from the flash tank as they are mixed.

A problem occurs in existing systems when the low temperature loads are shut off or removed from a system. For example, a grocery store may decide to downsize and remove freezers but keep produce shelves. As another example, freezers may shut off during regular a cooling cycle or may be taken offline for maintenance. In these systems, there may not be any (or there may be an insufficient amount of) refrigerant from a low temperature section to heat the refrigerant from the medium temperature section and/or gas from the flash tank. Consequently, the refrigerant that is received by the medium temperature compressor may be too cool for the medium temperature compressor to handle appropriately. For example, if the refrigerant is too cool, it may include a liquid component. The liquid may cause oil to foam in the medium temperature compressor as the refrigerant is compressed. As a result of the foam, a shutoff may trigger, and the compressor may be shut down.

Existing systems address this problem by including a hot gas dump valve off the medium temperature compressor. When the superheat of the refrigerant entering the medium temperature compressor is too low, the hot gas dump valve opens to direct refrigerant from the discharge of the medium temperature compressor back to the intake of the medium temperature compressor. Because the refrigerant discharged by the medium temperature compressor is hot, it heats the refrigerant at the medium temperature compressor intake, thus increasing the superheat of the refrigerant at the medium temperature compressor intake. This solution, however, decreases efficiency because the medium temperature compressor must re-compress refrigerant that it had already compressed. Additionally, the hot gas dump valve is expensive and increases the cost of the system.

This disclosure contemplates an unconventional cooling system that obviates the need for a hot gas dump valve by using a heat exchanger to direct heat back to the intake of the medium temperature compressor. The heat exchanger receives hot refrigerant discharged by the medium temperature compressor and a flash gas discharged by a flash tank. The heat exchanger transfers heat from the refrigerant from the medium temperature compressor to the flash gas. The heat exchanger then directs the flash gas to the intake of the medium temperature compressor to increase the superheat of the refrigerant in the medium temperature compressor. In this manner, the heat exchanger transfers heat from the discharge of the medium temperature compressor to the intake of the medium temperature compressor. Certain embodiments of the cooling system are described below.

According to an embodiment, an apparatus includes a high side heat exchanger, a flash tank, a first load, a first compressor, and a heat exchanger. The high side heat exchanger removes heat from a refrigerant. The flash tank stores the refrigerant from the high side heat exchanger and to discharge a flash gas. The first load uses the refrigerant from the cool a first space proximate the first load. The first compressor compresses the refrigerant from the first load. The heat exchanger transfers heat from the refrigerant from the first compressor to the flash gas before the refrigerant from the first compressor reaches the high side heat exchanger. The heat exchanger directs the flash gas to the first compressor after heat from the refrigerant from the first compressor is transferred to the flash gas and directs the refrigerant from the first compressor to the high side heat exchanger after heat from the refrigerant from the first compressor is transferred to the flash gas.

According to another embodiment, a method includes removing, by a high side heat exchanger, heat from a refrigerant and storing, by a flash tank, the refrigerant from the high side heat exchanger. The method also includes discharging, by the flash tank, a flash gas and using, by a first load, the refrigerant from the cool a first space proximate the first load. The method further includes compressing, by a first compressor, the refrigerant from the first load and transferring, by a heat exchanger, heat from the refrigerant from the first compressor to the flash gas before the refrigerant from the first compressor reaches the high side heat exchanger. The method also includes directing, by the heat exchanger, the flash gas to the first compressor after heat from the refrigerant from the first compressor is transferred to the flash gas and directing, by the heat exchanger, the refrigerant from the first compressor to the high side heat exchanger after heat from the refrigerant from the first compressor is transferred to the flash gas.

According to yet another embodiment, a system includes a high side heat exchanger, a flash tank, a first load, a first compressor, a second load, a second compressor, and a heat exchanger. The high side heat exchanger removes heat from a refrigerant. The flash tank stores the refrigerant from the high side heat exchanger and to discharge a flash gas. The first load uses the refrigerant from the cool a first space proximate the first load. The first compressor compresses the refrigerant from the first load. The second load uses the refrigerant from the flash tank to cool a second space proximate the second load. The second compressor compresses the refrigerant from the second load. The first compressor compresses the refrigerant from the second compressor. The heat exchanger transfers heat from the refrigerant from the first compressor to the flash gas before the refrigerant from the first compressor reaches the high side heat exchanger. The heat exchanger directs the flash gas to the first compressor after heat from the refrigerant from the first compressor is transferred to the flash gas and directs the refrigerant from the first compressor to the high side heat exchanger after heat from the refrigerant from the first compressor is transferred to the flash gas.

Certain embodiments provide one or more technical advantages. For example, an embodiment increases the superheat of refrigerant at a medium temperature compressor when the system is lacking a low temperature load. As another example, an embodiment prevents a medium temperature compressor from foaming and shutting down when the superheat of the refrigerant at the intake of the medium temperature compressor is insufficient. Certain embodiments may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.

Embodiments of the present disclosure and its advantages are best understood by referring toof the drawings, like numerals being used for like and corresponding parts of the various drawings.

A typical commercial refrigeration system includes a medium temperature section (e.g., produce shelves) and a low temperature section (e.g., freezers). A low temperature compressor compresses the refrigerant from the low temperature section. A medium temperature compressor compresses a mixture of the refrigerant from the medium temperature section, a flash gas from a flash tank, and the compressed refrigerant from the low temperature compressor. Thus, the temperature of the refrigerant from the low temperature section and the temperature of the refrigerant from the medium temperature section and/or gas from the flash tank affect the temperature of the mixture received at the medium temperature compressor. Typically, the refrigerant from the low temperature section heats the refrigerant from the medium temperature section and/or gas from the flash tank as they are mixed.

A problem occurs in existing systems when the low temperature loads are shut off or removed from a system. For example, a grocery store may decide to downsize and remove freezers but keep produce shelves. As another example, freezers may shut off during regular a cooling cycle or may be taken offline for maintenance. In these systems, there may not be any (or there may be an insufficient amount of) refrigerant from a low temperature section to heat the refrigerant from the medium temperature section and/or gas from the flash tank. Consequently, the refrigerant that is received by the medium temperature compressor may be too cool for the medium temperature compressor to handle appropriately. For example, if the refrigerant is too cool, it may include a liquid component. The liquid may cause oil to foam in the medium temperature compressor as the refrigerant is compressed. As a result of the foam, a shutoff may trigger, and the compressor may be shut down.

Existing systems address this problem by including a hot gas dump valve off the medium temperature compressor. When the superheat of the refrigerant entering the medium temperature compressor is too low, the hot gas dump valve opens to direct refrigerant from the discharge of the medium temperature compressor back to the intake of the medium temperature compressor. Because the refrigerant discharged by the medium temperature compressor is hot, it heats the refrigerant at the medium temperature compressor intake, thus increasing the superheat of the refrigerant at the medium temperature compressor intake. This solution, however, decreases efficiency because the medium temperature compressor must re-compress refrigerant that it had already compressed. Additionally, the hot gas dump valve is expensive and increases the cost of the system.

This disclosure contemplates an unconventional cooling system that obviates the need for a hot gas dump valve by using a heat exchanger to direct heat back to the intake of the medium temperature compressor. The heat exchanger receives hot refrigerant discharged by the medium temperature compressor and a flash gas discharged by a flash tank. The heat exchanger transfers heat from the refrigerant from the medium temperature compressor to the flash gas. The heat exchanger then directs the flash gas to the intake of the medium temperature compressor to increase the superheat of the refrigerant in the medium temperature compressor. In this manner, the heat exchanger transfers heat from the discharge of the medium temperature compressor to the intake of the medium temperature compressor. Certain embodiments of the cooling system are described below.

In certain embodiments, the superheat of the refrigerant at the intake of a medium temperature compressor is increased without using a hot gas dump valve. in some embodiments, heat from refrigerant discharged by a medium temperature compressor is returned to the intake of the medium temperature compressor by a heat exchanger. The cooling system will be described using.will describe an existing cooling system with a hot gas dump valve.describe the cooling system with a heat exchanger.

illustrates an example cooling system. As seen in, systemincludes a high side heat exchanger, a flash tank, a medium temperature load, a low temperature load, a low temperature compressorhaving a suction side input and a discharge side output, a medium temperature compressorhaving a suction side input and a discharge side output, a flash gas bypass valve, and a hot gas dump valve. Generally, hot gas dump valveis opened to allow the hot discharge from medium temperature compressorto return to the intake (e.g., the suction side) of medium temperature compressorwhen a temperature and/or superheat of the refrigerant mixture at the intake of medium temperature compressoris too low. As a result, the temperature and/or superheat of the refrigerant at the intake is increased.

High side heat exchangerremoves heat from a refrigerant (e.g., carbon dioxide). When heat is removed from the refrigerant, the refrigerant is cooled. This disclosure contemplates high side heat exchangerbeing operated as a condenser and/or a gas cooler. When operating as a condenser, high side heat exchangercools the refrigerant such that the state of the refrigerant changes from a gas to a liquid. When operating as a gas cooler, high side heat exchangercools gaseous refrigerant and the refrigerant remains a gas. In certain configurations, high side heat exchangeris positioned such that heat removed from the refrigerant may be discharged into the air. For example, high side heat exchangermay be positioned on a rooftop so that heat removed from the refrigerant may be discharged into the air. As another example, high side heat exchangermay be positioned external to a building and/or on the side of a building. This disclosure contemplates any suitable refrigerant (e.g., carbon dioxide) being used in any of the disclosed cooling systems.

Flash tankstores refrigerant received from high side heat exchanger. This disclosure contemplates flash tankstoring refrigerant in any state such as, for example, a liquid state and/or a gaseous state. Refrigerant leaving flash tankis fed to low temperature loadand medium temperature load. In some embodiments, a flash gas and/or a gaseous refrigerant is released from flash tank. By releasing flash gas, the pressure within flash tankmay be reduced.

Flash gas bypass valvecontrols the flow of flash gas from flash tankto medium temperature compressor. When valveis open, a flash gas can flow from flash tank, through valve, to medium temperature compressor. When valveis closed, the flash gas cannot flow from flash tankto medium temperature compressor. By allowing flash gas to flow from flash tankto medium temperature compressor, an internal pressure of flash tankis controlled and/or maintained.

Systemincludes a low temperature portion and a medium temperature portion. The low temperature portion operates at a lower temperature than the medium temperature portion. In some refrigeration systems, the low temperature portion may be a freezer system and the medium temperature system may be a regular refrigeration system. In a grocery store setting, the low temperature portion may include freezers used to hold frozen foods, and the medium temperature portion may include refrigerated shelves used to hold produce. Refrigerant flows from flash tankto both the low temperature and medium temperature portions of the refrigeration system. For example, the refrigerant flows to low temperature loadand medium temperature load. When the refrigerant reaches low temperature loador medium temperature load, the refrigerant removes heat from the air around low temperature loador medium temperature load. As a result, the air is cooled. The cooled air may then be circulated such as, for example, by a fan to cool a space such as, for example, a freezer and/or a refrigerated shelf. As refrigerant passes through low temperature loadand medium temperature load, the refrigerant may change from a liquid state to a gaseous state as it absorbs heat. This disclosure contemplates including any number of low temperature loadsand medium temperature loadsin any of the disclosed cooling systems.

Refrigerant flows from low temperature loadand medium temperature loadto compressorsand. This disclosure contemplates the disclosed cooling systems including any number of low temperature compressorsand medium temperature compressors. Both the low temperature compressorand medium temperature compressorcompress refrigerant to increase the pressure of the refrigerant. As a result, the heat in the refrigerant may become concentrated and the refrigerant may become a high-pressure gas. Low temperature compressorcompresses refrigerant from low temperature loadsand sends the compressed refrigerant to medium temperature compressor. Medium temperature compressorcompresses a mixture of the refrigerant from low temperature compressorand medium temperature loadand/or gas from flash tank. Medium temperature compressorthen sends the compressed refrigerant to high side heat exchanger.

In certain instances, low temperature loadmay not be operating fully or may be removed from systemor shut down. In these instances, there may not be enough hot refrigerant from low temperature compressorto mix with the refrigerant from medium temperature loadand/or gas from flash tankto raise the superheat of the refrigerant at the intake of medium temperature compressor. As a result, the refrigerant compressed by medium temperature compressormay not be sufficiently hot and may even include a liquid component. This liquid component reduces the efficiency of medium temperature compressorand may cause medium temperature compressorto foam, which could lead to a shut down.

Hot gas dump valvecontrols the flow of refrigerant discharged by medium temperature compressorto increase the temperature and/or superheat of the refrigerant at the intake of medium temperature compressor. When valveis open, part of the discharged refrigerant flows back to the intake of medium temperature compressor. There, the hot, discharged refrigerant mixes with the refrigerant from medium temperature loadand/or gas from flash tankand low temperature compressor. As a result, the temperature and/or superheat of the intake is increased. When valveis closed, the discharged refrigerant flows to high side heat exchanger. Generally, hot gas dump valveis undesirable because it reduces efficiency by making medium temperature compressorre-compress refrigerant that it has already compressed. Additionally, hot gas dump valveis expensive, which drives up the cost of cooling system.

illustrate example cooling systems that obviate the need for hot gas dump valve. Generally, these systems use a heat exchanger to transfer heat back to the intake of medium temperature compressor.

illustrates an example cooling system. As seen in, systemincludes a high side heat exchanger, a flash tank, a medium temperature load, a medium temperature compressor, a flash gas bypass valve, a heat exchanger, and an oil separator. Generally, heat exchangertransfers heat from the refrigerant discharged by medium temperature compressorto a flash gas discharged by flash tank. The heated flash gas then mixes with the refrigerant at the intake of medium temperature compressorto heat that refrigerant. In this manner, systemtransfers heat from the discharge of medium temperature compressorback to the intake of medium temperature compressor. This transfer of heat allows medium temperature compressorto operate efficiently even when there may be low temperature loads missing from systemin certain embodiments.

High side heat exchanger, flash tank, medium temperature load, medium temperature compressor, and flash gas bypass valveoperate similarly as they did in cooling system. For example, high side heat exchangerremoves heat from a refrigerant. Flash tankstores the refrigerant. Medium temperature loaduses the refrigerant to cool a space proximate medium temperature load. Medium temperature compressorcompresses the refrigerant from medium temperature load. Flash gas bypass valveopens and closes to control a flow of flash gas discharged by flash tank. In this manner, the refrigerant is cycled through systemto cool a space.

An important difference between systemand systemis that systemdoes not include a low temperature load or low temperature compressor. As a result, there is no hot refrigerant from a low temperature compressor to mix with the refrigerant from medium temperature loadand/or gas from flash tankat the intake of medium temperature compressor. Thus, the temperature and/or superheat of the refrigerant at the intake of medium temperature compressormay not be high enough for medium temperature compressorto compress the refrigerant efficiently. Additionally, the refrigerant may include liquid components that cause medium temperature compressorto foam and/or shut down.

Systemaddresses the insufficient temperature and/or superheat at the intake of medium temperature compressorby transferring heat from the discharge of medium temperature compressorback to the intake of medium temperature compressorusing flash gas discharged by flash tank. Generally, systemuses heat exchangerto transfer heat from the refrigerant discharged by medium temperature compressorto flash gas discharged by flash tank. The heated flash gas is then directed to the intake of medium temperature compressorwhere it mixes with the refrigerant from medium temperature load. As a result, the temperature and/or superheat of the refrigerant at the intake of medium temperature compressoris increased.

Heat exchangerincludes tubes, pipes, and/or plates that transfer heat between two fluids flowing through heat exchanger. These components may be made of metal to support the heat transfer. In system, heat exchangeris positioned between high side heat exchangerand medium temperature compressor. Heat exchangerreceives refrigerant from medium temperature compressorand flash gas from flash tank. As the refrigerant and the flash gas flow through heat exchanger, heat is transferred between these two fluids. For example, heat from the refrigerant from medium temperature compressoris transferred to the flash gas, thus heating the flash gas and cooling the refrigerant. After heat transfer is complete, heat exchangerdirects the refrigerant to high side heat exchangerand the flash gas to medium temperature compressor. By removing heat from the refrigerant from medium temperature compressor, the efficiency of systemis improved because high side heat exchangerdoes not need to work as hard to remove heat from the refrigerant in certain embodiments. Additionally, by heating the flash gas, the efficiency of medium temperature compressoris improved because the temperature and/or superheat of the refrigerant at the intake of medium temperature compressorincreases in certain embodiments. Heat exchangerthus obviates the need for hot gas dump valvein system.

In certain embodiments, heat exchangerallows for a state change to occur in the flash gas from flash tank. For example, the flash gas from flash tankmay include a liquid component and a gaseous component when the flash gas reaches heat exchanger. By transferring heat to the flash gas, heat exchangermay cause the liquid component in the flash gas to evaporate, thereby resulting in a flash gas that is only gaseous. The gaseous flash gas is then directed to medium temperature compressor. In this manner heat exchangerreduces the odds that a liquid reaches medium temperature compressor, which reduces the chances that medium temperature compressorfoams and/or shuts down.

In certain embodiments, systemuses oil separatorto separate an oil from the refrigerant discharged by medium temperature compressor. Oil separatorreceives the refrigerant from medium temperature compressorand separates an oil from the refrigerant. Oil separatorthen directs the refrigerant to heat exchanger. In particular embodiments, by separating the oil from the refrigerant, the efficiency of systemis improved because oil is prevented from flowing to other components of system, such as heat exchangerand/or high side heat exchanger. Oil may cause these components to be damaged and/or clogged. Thus, oil separatorimproves the efficiency and lifespan of other components of systemby separating oil from the refrigerant flowing in system. This disclosure contemplates that oil separatoris optional and that certain cooling systems may not include oil separator.

illustrates an example cooling system. As shown in, systemincludes a high side heat exchanger, a flash tank, a medium temperature load, a low temperature load, a low temperature compressor, a medium temperature compressor, a flash gas bypass valve, a heat exchanger, an oil separator, a valve, and a valve. Generally, systemobviates the need for a hot gas dump valve by transferring heat from the discharge of medium temperature compressorto the intake of medium temperature compressorusing heat exchanger. As a result, the temperature and/or superheat of the intake of medium temperature compressoris increased which improves the efficiency of medium temperature compressorand prevents foaming and/or shutdown in certain embodiments.

High side heat exchanger, flash tank, medium temperature load, low temperature load, low temperature compressor, medium temperature compressor, flash gas bypass valve, heat exchanger, and oil separatoroperate similarly as they did in systemsand. For example, high side heat exchangerremoves heat from a refrigerant. Flash tankstores the refrigerant. Medium temperature loadand low temperature loaduse the refrigerant to cool spaces proximate those loads. Low temperature compressorcompresses the refrigerant from low temperature load. Medium temperature compressorcompresses the refrigerant from medium temperature loadand/or gas from flash tankand low temperature compressor. Flash gas bypass valveopens and closes to control a flow of flash gas from flash tank. Heat exchangertransfers heat from a refrigerant discharged by medium temperature compressorto the flash gas discharged by flash tank. After heat transfer is complete, heat exchangerdirects the refrigerant to high side heat exchangerand the flash gas to medium temperature compressor. Oil separatorseparates an oil from the refrigerant discharged by medium temperature compressor.

An important difference between systemand systemis that systemincludes a low temperature section such as, for example, low temperature loadand low temperature compressor. As a result, the refrigerant from medium temperature loadmixes with hot refrigerant from low temperature compressorbefore reaching medium temperature compressor. In certain instances, however, the refrigerant from low temperature compressordoes not supply enough heat to the refrigerant from medium temperature loadto allow medium temperature compressorto operate efficiently. For example, low temperature loadmay be small and/or not running at full capacity. As a result, the refrigerant produced by low temperature compressor, although hot, is not of a sufficient volume to provide sufficient heat to the refrigerant from medium temperature load. As another example, during the summer when the ambient temperature is high, there may not be enough heat energy in the refrigerant from medium temperature loadand/or low temperature compressorto allow medium temperature compressorto operate efficiently.

In these instances, heat exchangercan transfer heat from the refrigerant discharged by medium temperature compressorto flash gas discharged by flash tank. The heated flash gas then mixes with the refrigerant from medium temperature loadand the refrigerant from low temperature compressorat the intake of medium temperature compressor. As a result, the intake of medium temperature compressormay have sufficient superheat to allow medium temperature compressorto operate efficiently in certain embodiments.

Valvesandare controlled to control the flow of flash gas in system. For example, when the refrigerant at the intake of medium temperature compressordoes not have a sufficiently high temperature and/or superheat, valvesandmay operate in a first mode of operation to allow flash gas from flash tankto be heated in heat exchanger. During this first mode of operation, valvemay be open and valvemay be closed. As a result, flash gas from flash tankflows through valveto heat exchanger. Heat exchangerthen transfers heat from the refrigerant from medium temperature compressorto the flash gas. Heat exchangerthen directs the flash gas to medium temperature compressorwhere the heated flash gas mixes with the refrigerant from medium temperature loadand low temperature compressor. When the temperature and/or superheat at the intake of medium temperature compressoris sufficiently high, valvesandare controlled to operate in a second mode of operation. During the second mode of operation, valveis closed and valveis open. As a result, flash gas from flash tankflows through valveto medium temperature compressorbypassing heat exchanger. In this manner, the flow of flash gas from flash tankis controlled such that the temperature and/or superheat at the intake of medium temperature compressoris controlled.

In certain embodiments, valveis a check valve. Flash gas from flash tankcan flow through valvewhen a pressure of the flash gas exceeds a threshold that is set for valve. Thus, valveopens when the pressure of the flash gas exceeds the threshold and closes when the pressure of the flash gas falls below the threshold. The pressure of the flash gas is controlled by opening and/or closing valve. By opening valve(e.g., during the first mode of operation discussed above), flash gas is directed to heat exchanger, thus reducing the pressure of the flash gas at valve. When valveis closed (e.g., during the second mode of operation discussed above), the pressure of the flash gas at valveincreases. When the pressure of the flash gas exceeds the threshold, valveopens and the flash gas flows to medium temperature compressor, bypassing heat exchanger.

Certain embodiments may exclude valve. In these embodiments, flash gas flows from flash tankthrough heat exchangerto medium temperature compressorwhen valveis closed (e.g., during the first mode of operation discussed above). When valveis open (e.g., during the second mode of operation discussed above), flash gas flows through valveto medium temperature compressor, bypassing heat exchanger. In this manner, the flow of flash gas from flash tankis controlled even though valveis missing from the system.

is a flow chart illustrating a methodof operating an example cooling system. In particular embodiments, various components of cooling systemsandperform the steps of method. By performing these steps, the components obviate the need for a hot gas dump valve in the cooling system.

In step, a high side heat exchanger removes heat from a refrigerant. A flash tank stores the refrigerant in step. In step, the flash tank discharges a flash gas. A load uses the refrigerant to cool a space in step. In step, a compressor compresses the refrigerant.

A heat exchanger transfers heat from the refrigerant from the compressor to the flash gas discharged by the flash tank in step. The heat exchanger then directs the flash gas to the compressor in step. In this manner, heat from the refrigerant discharged by the compressor is directed back to the intake of the compressor to heat the refrigerant at the intake of the compressor. As a result, the efficiency of the compressor is improved in certain embodiments. In step, the heat exchanger directs the refrigerant to the high side heat exchanger.

Modifications, additions, or omissions may be made to methoddepicted in. Methodmay include more, fewer, or other steps. For example, steps may be performed in parallel or in any suitable order. While discussed as systemsand/or(or components thereof) performing the steps, any suitable component of systemsand/ormay perform one or more steps of the method.

Modifications, additions, or omissions may be made to the systems and apparatuses described herein without departing from the scope of the disclosure. The components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses may be performed by more, fewer, or other components. Additionally, operations of the systems and apparatuses may be performed using any suitable logic comprising software, hardware, and/or other logic. As used in this document, “each” refers to each member of a set or each member of a subset of a set.

This disclosure may refer to a refrigerant being from a particular component of a system (e.g., the refrigerant from the medium temperature compressor, the refrigerant from the low temperature compressor, the refrigerant from the flash tank, etc.). When such terminology is used, this disclosure is not limiting the described refrigerant to being directly from the particular component. This disclosure contemplates refrigerant being from a particular component (e.g., the high side heat exchanger, the medium temperature compressor, etc.) even though there may be other intervening components between the particular component and the destination of the refrigerant. For example, the heat exchanger receives a refrigerant from the medium temperature compressor even though there may be an oil separator between the heat exchanger and the medium temperature compressor.

Although the present disclosure includes several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present disclosure encompass such changes, variations, alterations, transformations, and modifications as fall within the scope of the appended claims.